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Palmer R.E.,Mustang Engineering
11AIChE - 2011 AIChE Spring Meeting and 7th Global Congress on Process Safety, Conference Proceedings | Year: 2011

A financial analysis for an onsite facility to recover high purity propylene from refinery propane/propylene is put forward. The critical variables involved in the optimization of equipment sizes and operating costs for the recovery of high purity propylene by conventional distillation and distillation using a heat pump are examined. A capital cost estimate for each scheme and ranking based on an investment plus operating cost formula is then presented. Moreover, the discounted cash flow rate of return as a function of propylene value, utilities cost, and facility capacity is highlighted. The value of the PP feed stream is calculated as a function of the rate of return for the project and the other variables. This is an abstract of a paper presented at the 2011 AIChE Spring Meeting & 7th Global Congress on Process Safety (Chicago, IL 3/13-17/2011). Source

Zwerneman F.J.,Mustang Engineering | Digre K.A.,API Consultant
Proceedings of the Annual Offshore Technology Conference | Year: 2010

This paper summarizes the updating of API RP 2A Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms - Working Stress Design - API RP 2A-WSD 21 st Edition with Supplements 1, 2, and 3, to a 22 nd Edition. That 22 nd Edition is planned to be the last edition of API RP 2A-WSD. API RP 2A was due for a revisian. Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least every five years. A complete and thorough review of the document was long overdue. The 21 st edition was issued in December 2000, Supplement 1 in December 2002, Supplement 2 in September 2005, and Supplement 3 in October 2007. In addition, API desired to incorporate the content from API Bulletins 2INT-MET, 2INT-DG, and 2INT-EX plus accommodate development and alignment of API Recommended Practices 2SIM, 2MET, 2EQ, and 2GEO with ISO. In the process of making editorial revisions, it became obvious that some technical revisions were also needed. Copyright 2010, Offshore Technology Conference. Source

Wu W.J.,Mustang Engineering | Wu W.J.,Louisiana State University | Cai C.S.,Louisiana State University
Structural Engineering and Mechanics | Year: 2010

Excessive stay cable vibrations can cause severe problems for cable-stayed bridges. In this paper a semiactive Magnetorheological (MR) damper is investigated to reduce cable vibrations. The control-oriented cable-damper model is first established; a computer simulation for the cable-damper system is carried out; and finally a MR damper is experimentally used to reduce the cable vibration in a laboratory environment using a semiactive control algorithm. Both the simulation and experimental results show that the semiactive MR damper achieves better control results than the corresponding passive damper. Copyright © 2010 Techno Press. Source

Stith J.C.,University of Texas at Austin | Helwig T.A.,University of Texas at Austin | Williamson E.B.,University of Texas at Austin | Frank K.H.,Hirschfeld Industries | And 4 more authors.
Journal of Structural Engineering (United States) | Year: 2012

The stability of I-girders during erection can be difficult to assess because of the limited presence of bracing and uncertainty in the support conditions of the girders. The behavior of curved girders during the early stages of construction is complicated because the curved geometry can lead to significant torsion. This paper highlights results from a research study that included both field monitoring and parametric finite-element investigations. Curved I-shaped girders were instrumented and monitored during lifting to provide data to validate finite-element models. Both rotational displacements and stress were measured during the lifting process. In this paper, the writers compare data collected from field tests with results computed from detailed finite-element simulations. A prismatic and a nonprismatic girder (with two different cross sections) were considered in the investigation. The I-girders experienced both rigid body rotation and cross-sectional twist. Additionally, the torsional warping stresses were observed to be of the same order of magnitude as the strong-axis bending stresses. However, it should be noted that the total stresses were well below yielding. The fact that the stresses are low during lifting should not be confused with a noncritical stage in the safety of the girders. Although the applied stresses are low, the stresses necessary to buckle the girder or to cause large deformations are also relatively low because usually no bracing exists and limited restraint is provided to the girders during lifting. The finite-element models were able to capture the measured behavior accurately, providing insight into appropriate assumptions and critical features for modeling curved I-girders during lifting. © 2012 American Society of Civil Engineers. Source

Palmer R.E.,Mustang Engineering
12AIChE - 2012 AIChE Spring Meeting and 8th Global Congress on Process Safety, Conference Proceedings | Year: 2012

An update on the critical process design issues for hydrotreating diesel fuel to meet ultra-low sulfur diesel (ULSD) requirements based on the knowledge gained since ULSD regulations were put in place is presented. This is an abstract of a paper presented at the 2012 AIChE Spring Meeting and 8th Global Congress on Process Safety (Houston, TX 4/1-5/2012). Source

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